Prepaid wireless communications systems, in which a customer or subscriber prepays for usage of a communications system, has become increasingly popular in recent times. In such systems, the customer may purchase blocks of time for making voice telephone calls. For example, a customer can purchase 1000 minutes of air time with which to conduct wireless telephone calls. Upon connecting to the wireless communications system, the customer's account is authorized and authenticated and the call is allowed to proceed. The network monitors the customer's usage time and decrements from the customer's account. If the account becomes depleted, the system can either prompt the customer to purchase more time or the system can terminate the call. Prepaid wireless communications system enable the customer to budget an amount of airtime that will be used during a certain period of time, and to insure that the budget will not be exceeded unless the customer purchases more airtime.
However, current wireless prepay systems are limited to voice calls, in which blocks of time are purchased for use in making wireless voice telephone calls. With the increasing popularity and demand for wireless data transmission systems, including SMS, MMS, BREW and 802.11 systems for wireless LAN, a need for a prepaid wireless data transmission system which offers the same benefits as the prepaid wireless voice transmission systems exists.